1. Field of the Invention
This invention concerns chaff deployment systems, which are primarily employed in military aircraft. In particular, the present invention is an improved squib assembly for use in chaff deployment systems and similar applications.
2. Description of the Prior Art
Chaff deployment systems are used in military aircraft to deploy radar reflective chaff at the command of the operator of the aircraft, typically as a defensive measure to act as a decoy to enemy radar systems.
A typical chaff deployment system that is presently used includes a magazine having 30 chaff cartridges, such as RR180 chaff cartridges. Each cartridge has two chaff chambers extending lengthwise in the cartridge for containing the chaff material, which may be metalicized glass material or other types of chaff known in the art. The front end of each loaded cartridge is covered by an end cap. The back end of each cartridge is configured to receive a dual squib assembly. That assembly includes two squibs, each of which communicates with one of the chaff chambers and can be fired electrically to generate high pressure gases sufficient to force the end cap off and the chaff out of the corresponding chaff chamber.
The squib assembly includes structures for properly positioning the squibs, for sealing the joint between the squibs and the chaff chamber, for providing electrical energy to ignite the squibs, and for interfacing the squib assembly to the aircraft. The chaff cartridge magazine is typically connected to a chaff dispenser on the aircraft. The dispenser includes electrical contacts that correspond with the contacts on the array of squib assemblies. The base of each squib assembly is typically grounded, and each squib assembly has a center contact that conducts an electrical firing signal to each squib. One of the squibs in a squib assembly may be directly connected to the center contact, while the other squib may be connected through a diode, a resistor, or other means for allowing selective firing of the two squibs connected to the single contact.
The BBU48 is a prior art squib assembly for use with the above-described type of chaff dispensing system. The BBU48 assembly is shown in FIG. 1. It comprises two 1083-type squib components 12, and it includes many additional components, including a printed circuit board 14, a machined aluminum alloy base 16, a positive contact 18, a zener diode 20, a cover plate 22, and a pair of sealing gaskets 24, one around each squib component. The BBU48 is functionally adequate, but difficult and expensive to make, due to the number of parts and the amount of work required to fabricate and assemble the parts. Furthermore, the ground connection between the printed circuit board 22 and the machined base of the BBU48 relies on a mechanical compression connection, which is susceptible to open circuit faults caused by thermal cycling, mechanical shock and vibration.
It is desirable to provide a functionally equivalent and interchangeable dual squib assembly to replace the BBU48 that is easier and less expensive to assemble. It is further desirable to provide a dual squib assembly that has fewer parts and that has a correspondingly higher degree of ruggedness and reliability.